


Slotting Together

by kitkatt0430



Series: Leonard Snart Appreciation Week 2020 [4]
Category: The Flash (TV 2014)
Genre: Alternate Universe - Canon Divergence, Barry has quit the CCPD, Len is still rebuilding the Cold Gun, Len's not the only one struggling to put himself back together, M/M, Post Lewis Snart's death, Slow Build, mental health
Language: English
Status: Completed
Published: 2020-12-12
Updated: 2020-12-12
Packaged: 2021-03-10 08:40:16
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,892
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27967700
Author URL: https://archiveofourown.org/users/kitkatt0430/pseuds/kitkatt0430
Summary: Len comes back from a successful heist to find the Flash in his living room - dressed in civvies - inspecting the pieces of the Cold Gun laid out on the kitchen table."Looks like you're making good progress.""Did you break in here?"(Or Len's still putting the pieces of his life back together and it's a little disconcerting the way Barry seems to just slot right in.)
Relationships: Barry Allen/Leonard Snart, Leonard Snart & Lisa Snart, Mick Rory & Leonard Snart
Series: Leonard Snart Appreciation Week 2020 [4]
Series URL: https://archiveofourown.org/series/2036638
Comments: 15
Kudos: 230





	Slotting Together

**Author's Note:**

> For Leonard Snart Appreciation Week - Favorite Romantic Relationship
> 
> ColdFlash is, by far, my favorite romantic pairing for Len. Every scene they're in together, they're electric. It's all the pun-based flirting, no doubt. :D (My second favorite is ColdWave because Mick and Len as criminal husbands is adorable.)
> 
> While I didn't write Thaw intending to write a follow up to it, the open ending has been weighing on my mind a little so it looks like I'll be elaborating on it some after all.

Len made his own blueprints for the Cold Gun after forcing Ramon to make the second version. He didn't want to have to depend on the engineer for the next iteration of the gun and mapping out all the pieces gave Len the opportunity to indulge his own ideas.

There was, of course, the 'basic' model. The version that Cisco had made. Then there were a few blueprints Len had come up with over the last few months for upgrades to the gun. Upgrades that offered a better granularity of control and a sleeker casing... and his own version of the control software, minus the connection to STAR Labs' little eye in the sky. He had a few other ideas, but none were viable yet. But it did mean that he had to spend the first few days after Barry gifted him the sub zero micro particle generator finalizing a new set of blueprints. The design for the gun he was going to make.

The Cold Gun Mark III.

Once finalized, Len had his shopping list of items to gather. Some things he could purchase. Mostly legally. Other items he'd have to steal outright. No frills heists. He didn't want to catch the Flash's attention until after the gun was finished.

(It was nice to know he wasn't the only one looking forward to Captain Cold's return. Barry had indicated a rather unexpected attachment to their encounters that Len found himself wishing very much to indulge.)

As the purchased pieces began to pile up, Len started going after the items that would require theft instead.

The first required a simple warehouse theft. Break in, find the part, and get out before the security system finished rebooting and set off the alarm. From the moment he reset the alarm, he had twenty minutes on the clock.

Admittedly, Len could have purchased this particular item. But there was a reason he chose to steal the part instead. Aside from making it more difficult to trace the parts in his gun, Len had something to prove to himself. And, with fifteen minutes to spare as he drove away from the warehouse on his motorcycle, Len found he'd more than proved his point.

Once upon a time, Len became a thief because his father pressured him into it. It was an art Len perfected, to show his father how much better Len was than him. To show his father that Leonard Snart had no need of him. Somewhere along the way, it became a calling. And now...

Len loved the thrill of a well executed heist too much to ever give this up. Lewis Snart's death changed nothing. (Yet... at the same time, his death changed everything. There was a lightness to his actions that Len had never felt before. A sense of accomplishment and... fun that he'd always just... ignored.)

The second heist is an actual challenge and will gain him two of the three pieces he does actually need to steal. The control board and the cooling mechanism.

The irony of the Cold Gun - or at least ironic to anyone not well aware of the rules of thermodynamics - is that it could so easily overheat. The sub zero particle generator creates particles that, like the name suggests, create an instant sub zero freeze. The intensity of which varies depending upon the settings. The original design had one. The second version Ramon created had two. Len's version would have five. However, regardless of the intensity of the particle beam, the generator itself utilized a great deal of energy which in turn meant that it output a great deal of heat too. The cooling mechanism therefor was required to keep the Cold Gun from overheating.

The Cold Gun relied on redirecting a very small amount of the cold generated by the gun back in on itself. It had to have a specially calibrated setting for each setting the gun itself had for the particle beam, so that only exactly the right amount of cold particles were redirected. Not enough, the gun eventually overheated anyway. Too much and the gun would eventually 'backfire', overloading in the user's hands and sending spikes of sub zero particles all over the place until the gun destroyed itself entirely.

(Barry had made it look like an overload had caused Lewis Snart's death. Len's still not sure what to do with that, knowing that the kid staged a crime scene for his sake. He doesn't understand why Barry would do that for him.

Lisa called him an idiot, because it was apparently obvious. Not that she was willing to elucidate on the subject.)

* * *

After killing his father, Len's depression came back with a vengeance. Sometimes he felt like he was reliving the moment he iced Lewis every time his eyes shut. It made getting out of bed - and staying out of bed - difficult.

Lisa had been concerned. So concerned, in fact, that she'd cyber stalked Ramon until she figured out who the Flash really was and proceeded to sic Barry Allen on Len. Barry Allen who came to their safe house bringing blueberry pancakes, good cheer, and the first piece of the Cold Gun. And afterwards, Len started winning his struggle to get out of bed in the morning with more regularity.

Today, which was supposed to be the day of the control board and coolant system heist, was not a good day.

Len stared up at his ceiling, alarm shrieking BEEP BEEP BEEP BEEP over and over in his ears, and considers rolling over. The heist doesn't have to be today. His brain feels foggy, as just waking up enough to realize that the loud noise was the alarm and not an overgrown angry bird peeping in his ears was a struggle. He can't remember his dreams, but he feels unsettled by them anyway.

"You gonna shut that thing off?" Lisa asked, poking her head in the doorway.

He swatted the off button with his left hand and sat up, though he made no move to sweep the covers away and actually get up. Instead he just sat there, staring at his covers, until Lisa came over and pulled him into a hug. He leaned into her touch for a long while before saying, "if you'll make coffee, I'll be out in a few minutes."

"One fresh pot of coffee, coming up," Lisa promised, heading out the door and letting it shut behind her.

It still takes Len another minute - he counts the seconds - before he finally shoves his covers aside. He trades his pajamas for jeans and a shirt before heading out to join Lisa.

It's not a good day. But it doesn't have to be a bad one either.

* * *

The heist helps clear Len's mind. Helps him to focus as he keeps a mental count of the time. Unlike his fifteen minutes of leeway in the first heist, this one he completes with only thirty seconds to spare. He speeds through the city on his motorcycle afterwards, letting the twists and turns from roads picked at random bring him down off the high of a completed heist before heading back to his safehouse.

He'd left the pieces of the Cold Gun laid out on the kitchen table before he'd headed out for the heist. As Len enters the apartment, he sees someone standing over them - hands clasped behind their back - and Len pulls his gun on the intruder without a thought. Lisa had left at lunch time and would be out of town for the rest of the week. Mick hadn't come back from his out of town jaunt yet, so...

It's Barry who straightens up and turns to look at Len, amusement in his eyes as he ignores the gun. And why wouldn't he - Barry can catch bullets easily at this distance. "Looks like you're making good progress," Barry observed, a lilting grin on his face.

Putting his gun away, Len rolled his eyes and kicked the door shut behind him. "Did you break in here?"

"If I vibrate at the right speed, I can run through solid objects. Like locked doors," Barry told him, a smirk sliding onto his face. "Is it breaking in if I don't actually break anything?"

"Convenient," Len said, ignoring the bait. Kid knew as well as Len did that illegal entry was still called 'breaking in' even if the door still latched just fine afterwards. But the fact that Barry could do something like that... kind of attractive, really. And Len shouldn't be thinking that about someone who entered his safehouse without permission, but...

But this was Barry. And it seemed Barry Allen was the exception to so many of Len's rules.

"You'd make a good thief," Len teased.

"I would make an exceptional thief," Barry teased back, lighting up. "Too bad I enjoy the thrill of stopping crimes instead."

"Didn't stop any crime tonight, Scarlet," Len boasted, adding his haul to the table and sorting them into position amongst the rest. "Though you may find yourself there when your day job beckons."

"No more day job," Barry replied, a touch wistful. "Today was my last day. There was cake."

"So why are you here instead of with your little nerd friends?" Len settled at the table booting up the laptop he'd use to program the control board for the Cold Gun.

Barry shrugged. "They don't really understand why I quit. And Joe's taken it as a personal insult that I went through with it, which probably means its time for a new apartment."

"What about your dad? I heard Doc Allen was finally exonerated." Silence greeted Len's observation, so he turned his attention away from the computer in order to give the speedster his full focus.

Finally Barry answered. "He's living in a cabin out of state right now. Said he needed a change of scenery and he didn't want to be a distraction to me. But he wasn't even out a week before leaving, didn't tell me until he had everything lined up, wouldn't let me go with him for a few days to help settle him in... could barely even look at me." Barry's voice cracked, just a little, towards the end. "And why not? I've only got the exact same powers as the man who murdered his wife."

It seemed that Len wasn't the only one having bad days lately. He probably should have realized, what with the kid quitting his job. Even if Barry did at least seem to have a solid plan for where to go next, what with wanting a PhD.

"Did he actually say he's afraid of you?" Len tilted his head to the side and waited for the answer.

"No..."

"Then maybe you should ask him why the first thing he does after getting out of prison is push you away. Whether it's fifteen days or fifteen years, prison changes people. Maybe he's worried you won't like who he's changed into," Len offered.

Barry ran a hand over his face. "I hope it's something like that. But I guess just about any reason is better than him hating me for something I didn't ask for."

"While you're here... you can debug my programming. And no sneaking in anything that'll let STAR Labs track the gun. It won't have the ability to uplink to any satellites anyway." Len pulled up the code editor with his coolant system control program on it and turned the computer to Barry. "Hope you know Assembly language."

Barry grimaced. "I'm better with higher level languages. Got some reference books I can use to brush up on it real fast?"

Well... this ought to be interesting. Len pointed to one of the shelves in the living area and Barry took off, speeding through the books before settling back at the table. "I should be good for the next half hour at least. Reading at those speeds isn't the best for long term knowledge retention, but if I refresh it often enough then it'll stick around longer each time."

"I'll suppose I should order some Chinese..." Len grinned as Barry lit up. Though the kid's attention never left the computer screen, he rattled off a few requests, back tracked, and changed his order at least twice before settling on his final decision.

Barry's rambling shouldn't be nearly as endearing as Len finds it to be.

* * *

Lisa comes back with Mick. He walks into the apartment, takes one look at the kitchen table full of parts and the refrigerator that has milk, beer, and not much else, and immediately leaves, slamming the door behind him. Comes back a little over an hour later with groceries and mutters under his breath things like 'I'm Leonard Snart and I don't care if I get scurvy' and 'not the aspect of piracy that should be emulated here, dipshit' under his breath as he puts it all away.

Len's used to it. He rolls his eyes and lets Mick get his passive aggressive complaints out. The lasagna Mick makes after putting away the groceries is worth it. Honestly, if Mick hadn't been pigeonholed for his pyromania, he'd be a five star chef somewhere by now.

It makes Len stop and wonder. Who would he be if not for his father instilling a love of theft in him? An engineer? Bookstore owner? Tattoo artist? Len's got no idea. He just can't... see himself as anything but what he is. He can see everyone else's potential just fine. So why is he such a blank?

He buries himself in blankets early that evening and scowls at his alarm clock in the morning, considering dismantling it. But he hears Mick banging around in the kitchen already. The last thing Len wants is to deal with Mick dragging him out of bed instead of Lisa. So up Len gets.

* * *

"Do I know you?" Mick demands when he opens the door to Barry. Len slides up behind Mick and opens the door wider.

"Come on in, Barry." Len says, perfectly content to let the speedster ignore Mick's question.

Barry, however, is apparently not content to let it go. "I used to work as a CSI for the CCPD. So you probably saw me the last time they brought you in, though I'm sure you were busy doing your melodramatic evil criminal routine to take too much notice of the guy in the back with a laminate instead of a shield."

"Used to? They fire you or ya quit?" Mick's eying Barry suspiciously.

"I quit."

"Can't be that bad, then," Mick allowed. "So..." he looked between Barry and Len while Len really hoped Mick wasn't about to ask what he thought Mick was about to ask... "How long you two been fucking?"

"We're not," Barry squeaked, blushing.

"Barry got me the particle generator I need for the Cold Gun Mark III," Len said. "And he's been debugging my control unit's programming."

"Yeah, and what do you get out of it kid?" Mick shook his head. "You're off your game, Leonard." Then he wandered off into the living room to watch some football game on tv.

"Bet you're missing those friends of yours something awful now," Len observed mockingly.

He got a shrug in response. "Cisco's busy with Lisa today. And it would've been Ronnie's birthday, so Caitlin wanted to be alone. Joe's at work and he's still pissed at me for quitting."

"You okay being around Mick?" Len asked cautiously. He doesn't want these little visits to end, but if Barry's not comfortable around Mick then that's pretty much it.

But Barry just shrugged. "Lisa warned me she was bringing him back from out of town. So I sort of figured he'd be here."

And yet he came anyway. Len's not quite sure what to make of that yet. So he changes the subject. "Started looking at apartments yet?"

"Yeah. Trying to figure out my budget first. And I inherited a house just outside the city limits recently, so I'm trying to get that sold off." Inner city real estate was still doing well after the singularity, but a lot of the areas surrounding Central had emptied out real sudden as the reality of metas and potential world ending events sank in. It was a buyers market and depending on the property's value and aesthetic... could take a while to get rid of it.

Barry settled at the computer, discretely speed reading through the Assembly language books, and then went to debugging.

Len grabbed a beer and joined Mick on the couch. "He's Doc Allen's kid," Len finally said, when he couldn't take Mick's pointed silence and side-eyes any longer.

Mick nodded thoughtfully. 

* * *

Despite Mick's spectacular lack of brain to mouth filter, Barry continues to come around to the apartment.

It's feeling less like a safehouse these days and a little more like a home. Len should be concerned, getting so comfortable. But he likes the way Lisa pads around the place in her pajamas on the weekends and Mick starts experimenting with recipes and Barry shows up on random days to just retreat from the rest of the world.

And, honestly, they have some of the most ridiculous conversations.

While Mick's out one afternoon, but both Barry and Lisa are there, Len gets to hear the full story of how Lisa figured out the Flash's real identity. (And also her gloating a little over how she didn't have to kidnap anyone to figure it out.)

"Anyway, so you and Snow are in practically all of Cisco's pictures on Facebook these days and his closest friends in real life. And since Caitlin's boobs are too gorgeous and couldn't be safely bound to achieve the silhouette that bondage outfit gives you," at which point Barry was snickering, "I ruled her out."

"You ruled her out because of her boobs," Len repeated hesitantly, feeling altogether too gay for this conversation. "Not because she was sometimes in the same place as the Flash at the same time. Or how about when she was at STAR Labs with you while the Flash was clearly with me?"

"Lenny. Len. Leonard." Lisa drawled out his name very slowly. "For all we know, he can be in two places at the same time."

"I can make it look like I am, but I flicker like an old film reel," Barry offered.

"I want to see," Lisa chirped, prompting Barry to get up and demonstrate.

There was a small, but noticeable flicker as the two different Barry Allens circled the kitchen table before one of them settled back into his chair and the other disappeared entirely.

"I take it the more places you make it look like you are, the worse the flickering?" Len asked, interested despite himself.

"I have to be there long enough to be seen. It's not really practical in a fight, for the most part. But it's an entertaining party trick."

A few days later it's Lisa who's out and Mick who's there when Barry visits.

"Heard your dad got released from jail a couple of months back," Mick observed, handing Barry a beer. "How old are you?" he added, not letting go of the bottle, expression more mischievous than serious.

"If you really thought I was too young for alcohol, you wouldn't have assumed Len and I were fucking," Barry retorts, easily taking the bottle from him and twisting the top off.

Len wants to hear Barry say the word 'fucking' again. Wants to drag Barry into his bed and have his wicked way with the speedster and have good reasons to not want to get out of bed for a change.

"Fair enough. You're what, twenty-five?"

"Twenty-six, but I was in a coma for my twenty-fifth birthday. Which makes remembering my actual age frustrating." Barry takes a drink of the beer and then says, "but back to what you first said. Yeah, my dad is out of prison."

"So, why are you here instead of hanging out with him? Figured he'd want to spend some quality time with his kid." Mick's not looking, but Len is. He sees the way Barry goes ever so slightly rigid.

He hasn't followed Len's advice yet, that much is obvious.

"Remember him talking about you when he was stitchin' me up after a riot back at the Heights," Mick continued. "His bright kid off at college a year early was all he could talk about."

"Well I guess that changed," Barry said, tone carefully blank. "Because he left."

"Sorry to hear that." Mick paused a beat. "How'd he get out, though? Thought he was a lifer?"

"After fifteen years, the man who actually murdered my mother died under unusual circumstances, left behind a video confession of his crimes in his will, and I inherited all his wealth and properties. The confession was upheld in court, so my father was exonerated," and there's traces of amusement in Barry's intentionally bland tone now. Then Barry went to go pick the channel on the tv in the other room.

"Did that kid just confess to killing a man." There's respect in Mick's voice, though.

"No. Just to massively profiting from someone else's death," Len corrected.

Mick shook his head. "You don't start seducing him and I will."

Len pushes back against that possessive feeling in his chest, but it's no good. It tangles up in a knot over his lungs and leaves an irritated scowl on his face that only serves to make Mick laugh.

He looks at the Cold Gun on the table. It's not finished yet. Halfway there.

* * *

It takes a while to track down Henry Allen. Len takes a page out of Lisa's book and does a little cyberstalking to figure it out.

The little cabin in the woods, a few hours out of Central and one state over, is far more picturesque in person than it is in the pictures on Barry's facebook page. He's not sure he should be here, but if Barry won't talk to his father... then Len's just going to have to get the good doctor to pull his head out of his ass and talk to Barry instead.

He owes Barry... something. Or maybe Len's just doing this to chase away the nebulous little disgruntled feeling in his chest that pops up every time Barry avoids talking about his father. Henry Allen is a good man - at least, that's how Len remembers him. Sometimes, though, good men need a little kick in the ass to remind them where the line was drawn.

So Len gets off his bike and goes to knock at the door.

"Leonard," Henry greets him, tone equal parts surprised and wary.

"Hello, Doc. I heard your son was finally able to prove your innocence. Thought I'd stop by and see how you were doing. Pass along Mick's greetings." He paused a beat and then added, "and tell you to pull your head out of your ass. Barry's off his game and he's handling it fine right now but it isn't going to stay that way for long."

"What? Are you threatening..."

"No. As strange as it is, Barry's actually something of a friend these days. And trust me, we're both aware of how ridiculous that is given how your son's hobbies tend to clash with my own."

"And he's a CSI," Henry added, relaxing a little despite the fact he clearly realized Len knew Barry was the Flash.

"He didn't tell you, then," Len said. "He quit."

"He what?"

"He's planning on going back for his PhD in the spring. But he's already quit the CCPD in order to have more time to work on his application." Len shrugged. "I'm sure Captain Singh would give Barry back his job in a heartbeat, from what I've heard of the man. You'd know all of this if you hadn't shoved your son away so damn hard he was seeing stars."

Henry stared blankly at Len for a long moment and then opened the door to the cabin wide. "Why don't you come in and I'll make some coffee and you can finish telling me what an asshole I've been to my son."

Len smiled pleasantly and followed Henry inside.

* * *

"So how'd your meddling go?" Lisa asked.

"Mind your own business," Len grumbled.

"She's just following big brother's nosy example," Mick interrupted. "Kid coming for dinner tonight? He eats a lot - gotta plan out how many casseroles to make."

"Not tonight," Len responded shortly. He hadn't seen Barry since ambushing Henry and he was feeling a little twitchy about it.

"So I'm encouraging Cisco to hook up with Hartley," Lisa said abruptly.

"Who's Hartley?" Mick asked.

"Gray hat hacker and physicist - PhD - loosely affiliated with STAR Labs," Len filled in. He'd done his homework on the team, after all. "Why are you trying took up Cisco with someone else? Friends with benefits thing not working out after all?"

"No, Cisco and I are going to keep having sex." Lisa smirked when Len grimaced. "But I don't do romance. And Cisco's a very romantic soul. So we're giving polyamory a try. Cisco and Hartley have some unresolved sexual tension that's really quite delicious and Hartley's comfortable with the idea of having a metamour. Still have some relationship negotiations to work out, but I think it's going to be a win for all of us."

There was a long silence and then Len noticed Lisa giving him an expectant look. "What?"

"While you were visiting Doctor Allen, did you get his blessing to date his son?" she asked primly.

"When I can finally use the new Cold Gun," Len told her solemnly, "I'm using the lowest setting to ice your feet to the floor." That was the setting that would be safe-ish to use on normal people and not just speedsters, assuming Len had done his math right.

Len's math was always correct.

* * *

The last piece of the Cold Gun's interior workings slides into place and Len closes up most of the casing. The part that covers the computer ports he's leaving exposed for now. He'll need to find some place where he can safely run the gun through it's paces and have it hooked up to a computer that'll monitor the outputs and let Len adjust the programming as needed.

He's good at this. In another life he probably could've been an engineer. It's easier to see that now than it was before. But the theft that netted him the gun's casing would've driven the point home even if the preceding two heists hadn't. Len loves the thrill and precision of a good theft. 

Len regrets how he became a thief, but he doesn't regret being one.

Lisa and Mick are both out tonight and Len's not expecting company. But he knows who it is when there comes a knocking at his door.

He opens the door wide for Barry to come in. He expects Barry to settle at the table or the counter or maybe pace around with nervous energy. Instead Barry lets Len close the door and then just stands there, staring at him.

"Got something on my face, Barry? Or you see something you like?" Len teased, smirking and expecting to get a rise out of Barry.

Barry looks amused. "You talked to my dad."

"And clearly now so have you."

"He said he's proud of me for going for my PhD," Barry hedged.

"Yeah? How is that application process going for you anyway?" 

"I've got a thesis advisor lined up. I'm looking forward to it a lot more than I realized I would." Barry looked like he wanted to say something else, but was hesitating.

So Len went for it. "So is he afraid of your powers or hate them or what?"

"He thinks they're amazing. That I'm amazing." Barry sounded like he could scarcely believe it. "Though he did make fun of me for befriending my most well known rival."

And, shit, Len did tell Henry they were friends, didn't he? There goes the reputation, not that he had much of that left by now anyway. Maybe, like his Cold Gun, it was time to build a new one.

"I'm never going to be a hero, Barry," Len warned, stepping forward and placing his hands on the other man's shoulders. There were plenty of reasons he shouldn't do this, but... he was a thief. He stole what he wanted... and what he wanted, was Barry Allen's heart. Metaphorically, of course.

Closing the rest of the distance between them, Barry muttered, "then it's a good thing I want a thief," before pressing his mouth against Len's.

(They're still kissing by the time Mick gets back.

"It's about damn time. I brought groceries. Can Barry just put this all away real fast, or do I need to keep pretending I haven't figured out your boyfriend's the Flash, Len?"

Len groans and slumps onto a kitchen chair while Barry just grins and puts away Mick's purchases. Mick just looks unnecessarily smug about the whole thing.

"So... has the friction from running ever set your clothes on fire?" Mick asked eagerly. "At least your shoes have to have been set on fire, right?"

Len sinks lower in his seat, smile hidden behind his hands, as Barry laughs and answers Mick's questions.)

**Author's Note:**

> As a software engineer, I do not recommend writing things in Assembly if you can avoid it. Assembly sucks. Len is a masochist for using it.
> 
> This verse may have one more follow up in it. Though if it does it'll probably be mostly Barry's PoV and involve Zoom... it's more of a nebulous idea, but we'll see.


End file.
